Conventionally, there is a known technique for a satellite positioning system including a GPS receiver and a GPS server. In the technique, the GPS server receives ionospheric information intermittently transmitted based on events in the ionospheric layer such as sunrise, noon, and sunset, creates an ionospheric model, estimates Ionospheric error, and supplies the information of the estimated ionospheric error to the GPS receiver (see, for example, Patent Document 1).
Patent Document 1: Japanese Patent Application Publication No. 2005-517931.